I have over 5k miles up and down California using the goal post/ roof rack system. The benefit of it is it leaves you a covered truck bed to keep camping gear in.
Use lashing straps if theres too much wobble, but with two yaks there is not much.
I would agree that if a weld does break you are more than screwed.
I've been meaning to add extra weld supports, that would end that risk.
For the removeable roof rack, I use malone cradles ($100 for two) on a $25 Pep boys 1'' bar rack. I use a extra lashing strap through the truck cab to hold it down good.
http://www.kayakfishingstuff.com/Mer...Category_Code=
